What is respiration? Respiration often means inhaling and exhaling or the process of breathing. Respiration includes the process of taking in oxygen to oxidize food. This is called oxidation. In oxidation, energy is produced while carbon dioxide and water are released as by-products. Respiration is the exchange of gases --- oxygen and carbon dioxide.

RESPIRATORY SYSTEM

Main Parts of the Respiratory System Nose Pharynx Larynx Trachea Lungs

NOSE The nose has two openings called nostrils. The air enters the nasal passages through it. The air that you breathe must be cleaned, warmed and moistened before it reaches your lungs.

NOSE DETAILS The hairs in your nostrils filter the larger particles of dust and dirt as air enters the nostrils. The tiny hairs lining your nasal passage are called cilia and it works with a moist tissue lining called mucous membrane.

Function of cilia and mucous membrane The cilia filter the smaller particles of dust and dirt. The moist mucous membrane helps in catching particles of dirt. The mucous membrane also warms and moistens the incoming air.

PHARYNX The pharynx is found at the back of your throat. The pharynx separates into two tubes namely the esophagus and the trachea. The trachea is a long tube that leads to your lungs. At the bottom of your pharynx is a flap of cartilage called epiglottis.

Role of Epiglottis The epiglottis opens and closes the trachea. It prevents the food from going to the trachea by closing it during swallowing. This explains why you cannot breathe while swallowing something. Most of the time, it is open to allow the flow of air in the breathing process.

LARYNX The larynx is found at the lower end of the pharynx. It is the enlarged upper portion of the trachea. It is also called the VOICE BOX.

Sound Production The larynx contains the vocal cords that vibrate when air passes through them. The vibration of the vocal cords, together with the movements of the mouth and tongue produces the sound of your voice.

TRACHEA OR WINDPIPE The trachea is a tube about 13 cm long. It is the tube leading to your lungs. The lower end of the trachea branches into two large tubes called bronchi. It is a tough, flexible passageway where air can move through all the time. When you move your head and neck, the trachea twists and stretches.

Cilia lining The trachea lies just in front of the esophagus at the lower part of the larynx. The inner wall of the trachea is lined with cilia. The cilia are again always in motion to prevent the dust particles and dirt from entering the lungs. It catches the particles that reach the windpipe.

Coughing and Sneezing The dust particles caught by the cilia are pushed out and up toward the throat and mouth for expulsion. This explains why we cough or sneeze when dirt gets into the upper respiratory tract.

LUNGS The lungs are the main organs for breathing. The left bronchus leads to the left lung while the right bronchus leads to the right lung. Each bronchus divides into smaller tubes called bronchial rami. These bronchial rami branches into smaller tubes called bronchial tubes or bronchioles. At the end of the bronchioles are tiny air sacs called alveoli.

Breathing Tree The bronchioles and alveoli look like the branches of a tree. The biggest branch is the bronchi. Bronchi are also covered with cilia and a thin film of mucus. The mucus traps dust and pollen before they reach the alveoli.

Lung Details Each lung contains about 300 million alveoli! Each alveolus is surrounded by tiny blood vessels called capillaries. The exchange of oxygen and carbon dioxide during the breathing process takes place in the capillaries of each alveolus.

THE PATH OF AIR INSIDE THE BODY

Breathing In Breathing in is called INHALING or INSPIRATION. When you inhale, you fill your lungs with air.

Breathing Out Breathing out is called EXHALING or EXPIRATION. When you exhale, you push air with more carbon dioxide out of the lungs.

Breathing Process Breathing is an involuntary process because we do not think about it when we do it. Breathing is important to keep us alive.

Breathing Body Parts The lungs are important and delicate organs. They are protected by a set of bones called rib cage. The rib cage forms the chest cavity where the lungs are found. There is a sheet of muscles at the lower part of the chest cavity called the diaphragm. The diaphragm separates the chest from the abdomen.

Breathing In Movements The rib cage and the diaphragm are important in the breathing process. When you inhale, the ribs move upward and outward while the diaphragm moves downward. The volume of the chest cavity becomes larger. The pressure inside it is lower than the air pressure outside your body. Air is drawn into the lungs by the atmospheric pressure outside the body.

Breathing Out Movements When you exhale, the ribs move downward and inward while the diaphragm moves upward. These actions make the chest cavity smaller. The pressure in the chest cavity becomes greater than the air outside the body. This causes the air to rush out of the lungs and out of the body.

Looking Back The respiratory system supplies the body with the oxygen it needs and relieves it of carbon dioxide during the process of RESPIRATION. The main parts of the respiratory system are the nose, pharynx, larynx, trachea and lungs.

Looking Back Breathing in is called inhaling and breathing out is called exhaling. The rib cage forms the chest cavity where the lungs are found. The diaphragm separates the chest from the abdomen. The rib cage and the diaphragm are important in the breathing process.

THE END